Efficacy Evaluation of Subunit Vaccine of Classical Swine Fever Virus(CHO-133D) for Virus Load and Shedding after Challenge
Subunit vaccine of Classical Swine Fever Virus(CHO-133D)was prepared by emulsifying E2 protein expressed in Chinese hamster ovary (CHO) cells with ISA 201 adjuvant.In order to evaluate the efficacy of the subunit vaccine,especially the viral shedding and load,and horizontal transmission post challenge,piglets aged 4～6-weeks were immunized twice at an interval 21 days.The vaccinated and unvaccinated control piglets were challenged with the Shimen strain of CSFV at 21st day after the second vaccination.Concurrently,a sentinel group was established,which was neither vaccinated nor challenged and lived in the same area of vaccinated groups.On the 16th day post-challenge all piglets were euthanized,and dissected tissues and organs were collected.The viral loads were detected using RT-qPCR in the blood samples,as well as in anal swabs,nasal swabs,and oral swabs of all piglets collected at the day 0,2,4,6,8,10,12,14,and 16 post challenge.Viral load in organs was detected using immunohistochemistry and RT-qPCR methods.Immunized group was 5/5 protected and 5/5 morbidity and mortality was observed in the control group.Virus was detected in all unvaccinated control piglets' samples for several days after challenged,but not detectable in vaccinated piglets' oral,nasal,and anal swabs after virus attack,as well as in bloods 12 days after challenge.Virus was also not detected in the samples of liver and kidney but detectable in some tonsil and lymph node samples vaccinated group.No virus was detected in all samples of sentinel group piglets,indicating that no horizontal transmission of the swine fever virus occurred during challenge.The immunohistochemical assay showed that virus was found in all organs of the unvaccinated group,but not in either the vaccinated or sentinel group after the challenge.The genetically engineered subunit CSFV (CHO-133D) vaccine can fully protect experimental pigs from attacks of the Shimen strain of CSFV.It is an effective vaccine for blocking the horizontal spread of the virus and providing a controlling of the swine fever epidemics in future clinical practice.
classical swine fever virusgenetic engineering subunit vaccineviral excretionviral load carriedthe horizontal spread of the virus
万方数据
维普
